紫外分光光度法在水中阴离子表面活性剂标准样品研制中的应用

研究了阴离子表面活性剂水溶液的紫外吸收特性,并将研究结果用于阴离子表面活性剂水质标样的稳定性,均匀性和定值工作,简化了操作手续,获得了准确的分析结果。     

Spatial succession modeling of biological communities: a multi-model approach

Strong spatial correlation may exist in the spatial succession of biological communities, and the spatial succession can be mathematically described. It was confirmed by our study on spatial succession of both plant and arthropod communities along a linear transect of natural grassland. Both auto-correlation and cross-correlation analyses revealed that the succession of plant and arthropod communities exhibited a significant spatial correlation, and the spatial correlation for plant community succession was stronger than arthropod community succession. Theoretically it should be reasonable to infer a site's community composition from the last site in the linear transect. An artificial neural network for state space modeling (ANNSSM) was developed in present study. An algorithm (i.e., Importance Detection Method (IDM)) for determining the relative importance of input variables was proposed. The relative importance for plant families Gramineae, Compositae and Leguminosae, and arthropod orders Homoptera, Diptera and Orthoptera, were detected and analyzed using IDM. ANNSSM performed better than multivariate linear regression and ordinary differential equation, while ordinary differential equation exhibited the worst performance in the simulation and prediction of spatial succession of biological communities. A state transition probability model (STPM) was proposed to simulate the state transition process of biological communities. STPM performed better than multinomial logistic regression in the state transition modeling. We suggested a novel multi-model framework, i.e., the joint use of ANNSSM and STPM, to predict the spatial succession of biological communities. In this framework, ANNSSM and STPM can be separately used to simulate the continuous and discrete dynamics.     

Spatial variability of soil heavy metals in the three gorges area: multivariate and geostatistical analyses

There is a growing concern about environmental contamination in the three gorges area. The objectives of this study were to investigate the spatial variability and the possible influence factors of seven heavy metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the center of this area based on multivariate and geostatistical approaches. All analyzed heavy metals were below their background levels, except Cd. The average concentrations of the analyzed elements in topsoil (0-20 cm) were 5.83 mg As kg(-1), 0.21 mg Cd kg(-1), 78.79 mg Cr kg(-1), 21.53 mg Cu kg (-1), 0.049 mg Hg kg(-1), 24.12 mg Pb kg(-1), and 68.5 mg Zn kg(-1). The concentration of As was mostly due to parent materials, whereas the source of Pb was mainly due to vehicle exhaust. The high concentration of Cd was resulted from agricultural practices and parent materials. The concentrations of Cr, Cu, Hg, and Zn were associated with parent materials and human activities.     

Risk assessment and distribution of soil Pb in Guangdong, China

In this study, the spatial distributions of soil lead (Pb) concentration in three horizontal soils in Guangdong, China, were surveyed and analyzed using geostatistics and geography information systems (GIS). Findings indicated that the Pb geometric mean concentration of 23.3 mg/kg in surface soils was found to be higher than those in global soils, which ranged from 2.3–235 mg/kg. In addition, the Pb geometric mean concentrations from A- to C-horizon were found to be 23.3, 27.2, and 28.6 mg/kg, respectively. The classification of a soil Pb environmental risk in an area was likewise presented based on the different levels of environmental quality of Pb and was done by GIS technology. Accordingly, there is a higher local concentration of Pb in the surrounding areas of Guangzhou where there is higher population density and in the north of Guangdong, which is a historic mining area. The results obtained by the environmental risk assessment reveal that about 46% of total surveyed area was above the background value, that is, 2.7% of the total area was at risk of pollution.     

Understanding the Price Dynamics in the Jiangsu SO2 Emissions Trading Program in China: A Multiple Periods Analysis

Because emissions permits can be considered to be a pseudo-commodity, the permit price in the emissions trading markets has already attracted great interest from the economic literature. This research took the Jiangsu sulfur dioxide (SO₂) emissions trading program in China as a case study to examine the price dynamics over the next 10 years (2011–2020) based on Jiangsu’s new SO₂ emissions trading policy design. An adaptive agent-based simulation model was developed to estimate the price dynamics as well as the impact of energy price, policy design, and new environmental regulation on the permit price. The results showed that the equilibrium price of the Jiangsu SO₂ emissions trading market is approximately 4.20 CNY/kg, and the permit price will fluctuate around this price if the other conditions are not changed. If the coal price increases during 2011–2016, the permit price will decline to 2.79 CNY/kg by 2020 under China’s current coal–electricity price mechanism. In addition, the banking mechanism will smooth the price fluctuations and the average permit price will be generally higher when banking is not allowed. Finally, the stricter environmental regulation will reduce the market supply of permits and will raise the permit price. According to China’s potential new SO₂ discharge standard, the permit price will jump to 11 CNY/kg. The quantification of the permit price dynamics can help power plants to make decisions on emissions trading.     

Comparative research on NIMBY risk acceptability between Chinese and Japanese college students

Along with the progressive acceleration of urbanization, the need to identify potentially troublesome “Not In My Back Yard” (NIMBY) facilities in the city is inevitable. To resolve NIMBY conflict, it is important to know people’s NIMBY risk acceptability for these facilities. A questionnaire survey was used among Chinese and Japanese college students to identify NIMBY risk acceptability. LISREL was used to construct a structural equation model to analyze the difference in NIMBY risk acceptability between the Chinese and Japanese college students. Factors that may affect NIMBY risk acceptability were analyzed: “perceiving utility,” “perceiving risk,” “trust in government,” “reasonable compensation,” and “procedural justice.” The findings show that Japanese students’ concerns were greater than Chinese students’ concerns. Perceiving utility and perceiving risk were the most important factors that affect people’s NIMBY risk acceptability, followed by procedural justice, trust in government, and reasonable compensation. There is a difference between the different cultural backgrounds in confronting the risk: Chinese students focus more on the reputation and value of real estate, while Japanese students pay more attention to environmental pollution and damage to health. Furthermore, cultural influences play a role in students’ risk perception. To improve the risk acceptability for NIMBY facilities and provide a basis for resolving NIMBY conflicts, it is necessary to ensure the benefits of the NIMBY facility while reducing environmental pollution. The findings of this study may be of interest for policy makers and practitioners to devise future NIMBY strategies.     

Assessment of trace element contamination in sediment cores from the Pearl River and estuary,South China: geochemical and multivariate analysis approaches

Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully.     

Crystallization and Mechanical Properties of Recycled Poly(ethylene terephthalate) Toughened by Styrene–Ethylene/Butylenes–Styrene Elastomer

Recycled poly(ethylene terephthalate) (R-PET) was blended with 15–30 wt% of styrene–ethylene/butylenes–styrene (SEBS) block copolymer and maleic anhydride grafted SEBS (SEBS-g-MA). Effects of nucleation and toughening of the elastomers were evaluated systematically by study of morphology, crystallization, thermal and mechanical properties of the blend. The addition of 30 wt% SEBS promoted the formation of co-continuous structure of the blend and caused the fracture mechanism to change from strain softening to strain hardening. Addition of SEBS-g-MA resulted in significant modification of phase morphology and obviously improved the impact strength. The compatibilization reaction of PET with SEBS-g-MA accelerated the crystallization of PET and increased the crystallinity. The shifts in glass transition temperature of PET towards that of SEBS-g-MA and the higher modulus for R-PET/SEBS-g-MA (70/30) blend found by DMA are also indications of better interactions under the conditions of compatibilization and interpenetrating structure.     

Application of response surface methodology to the treatment landfill leachate in a three-dimensional electrochemical reactor

The influence of different variables on the removal of ammonia nitrogen and COD from landfill leachate was investigated in a three-dimensional electrochemical reactor. Box–Behnken statistical experiment design and the response surface methodology were used to investigate operating condition effects, such as current density, activated carbon to water ratio and the reaction time, on ammonia nitrogen removal efficiency and COD removal efficiency. The positive and negative effects of variables and the interaction between variables on ammonia nitrogen removal and COD removal were determined. The response surface methodology models were derived based on the results and the response surface plots were developed accordingly.